POS1490 ANTI-RO/SSA-ANTIBODIES AND ELECTROCARDIOGRAPHIC ABNORMALITIES IN PATIENTS WITH SYSTEMIC LUPUS ERYHEMATOSUS (SLE): DATA OF A MULTIDISCIPLINARY STUDY IN A MONOCENTRIC COHORT
Authors: M. Fredi, S. Bertocchi, E. Pedretti, R. Rovelli, A. Drera, F. Ravasio, M. Riccardi, L. Serafini, I. Cavazzana, E. Vizzardi, F. Franceschini
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Cardiovascular involvement is common in patients with SLE and heart rhythm disorders are frequent in addition to the manifestations included in the classification criteria ACR/EULAR 2019. Previous studies provided evidence that anti-Ro/SSA-positivity is an independent risk factor for marked QTc prolongation; suggesting that subjects who are anti-Ro/SSA-positive may represent a subgroup with an increased predisposition to ventricular arrhythmias, particularly when other QT-prolonging risk factors are concomitantly present [1]. <h3>Objectives</h3> The aim of this study is to estimate the prevalence of QTc-prolongation in a monocentric cohort and to evaluate possible correlation with the presence of anti-Ro/SSA-antibodies and other QT-prolonging risk factors. <h3>Methods</h3> An electrocardiographic study (ECG) was proposed to patients affected by SLE consecutively attending our Lupus Clinic from November 2021 to March 2022. All subjects were tested for anti-Ro/SSA-antibodies. Exclusion criteria included: severe valvulopathies, hypertrophic or dilated cardiomyopathy, previous implantation of pacemaker or implantable cardioverter-defibrillator. QTc measurement was calculated using the Bazett's formula and QTc-prolongation was defined according to American College of Cardiology (ACC)/American Heart Association (AHA) recommendations (QTc&gt;470 ms for males, QTc&gt;480 ms for females) [2]. Data on 24-hour ECG holter were available in 26 patients. <h3>Results</h3> One hundred and forty-one patients with SLE, consecutively attending our clinic, accepted to undergo an ECG, 128 (91%) females, 13 (9%) males; 124 (88%) Caucasians (median age 53.2 [IQR 42.3-58.7], median disease duration 20.0 years [12.0-28.2]). Median QTc was 415ms [IQR 394-436]; only 4/141 (2.8%), all Caucasian and female, had a prolonged QTc (Table 1). Sixty-eight (48%) patients were positive for anti-Ro/SSA-antibodies. No significant differences were observed between anti-Ro/SSA-positive vs. negative patients in term of QTc intervals (416.0 [395-437] ms vs 413.0 [392-432] ms; p=0.545) using Mann-Withney Test. Other electrocardiographic alterations were found: 4 first-degree atrioventricular blocks, 25 bundle branch blocks (BBB), 31 repolarization anomalies, 1 Wolff-Parkinson-White. Patients were grouped according to hydroxychloroquine (HCQ) therapy and antibody profile into 4 groups: HCQ+/Ro/SSA+(56, 39.7%), HCQ+/Ro/SSA-(58, 41.1%), HCQ-/Ro/SSA+ (12, 8.5%) and HCQ-/Ro/SSA- (15,106%); no statistical differences (p=0.178) were observed in QTc length comparing the 4 groups using ANOVA test. Twenty-six (18.4%) underwent a 24-hour ECG holter evaluation. None of these patients had a QTc prolongation, and no major elettrocardiographic anomalies were found. These patients were divided in 4 groups (as previously done for all patients). No statistical differences were found comparing the QTc of groups of patients (p=0.783). <h3>Conclusion</h3> These preliminary data show a lower prevalence of QTc prolongation compared to previous studies, with no differences between anti-Ro/SSA-positive and anti-Ro/SSA-negative patients. Otherwise, considering previous studies which observed a role of anti-Ro/SSA antibodies as an independent risk factor for QTc prolongation, further analysis will be performed in order to identify standardized markers for cardiovascular risk stratification. The evaluation of 24-hour ECG Holter in a larger number of patients and the characterization of anti-Ro/SSA (anti-Ro/SSA-52kD and anti-Ro/SSA-60kD) are ongoing. <h3>References</h3> [1]Lazzerini et al, Journal of the American Heart Association, 2021 [2]Drew BJ et Al. Circulation, 2010 <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.